【作者】 吴迪；

【导师】 胡锋；

【作者基本信息】 南京农业大学 ， 生态学， 2015， 博士

【摘要】 当前,农业生产中化肥的过量施用带来了一系列的环境问题,包括土壤酸化、土壤结构退化、微生物多样性下降、温室气体排放增加及硝酸盐淋溶污染地下水等。有机肥取代化肥已经成为可持续农业发展的趋势,但是有机肥本身也存在速效养分不足等问题。本研究试图在有机肥施用的过程中利用土壤动物(蚯蚓)进行生物调控,达到改善土壤质量、提高生产力和保护生态环境的多重目标。蚯蚓作为土壤生态系统的生态工程师,其生态系统服务与功能是土壤生态学的核心内容之一。蚯蚓可以通过掘穴、取食和排泄影响着土壤物理性质(土壤结构)、化学性质(养分有效性)及生物学性质(微生物活性及多样性)。虽然蚯蚓的益处已经被大量报道,但在田间条件下研究其对土壤、作物和生态环境的综合影响的报道较为罕见。在前人研究的基础上,为了更全面了解蚯蚓的生态系统服务功能,本研究设计了两个蔬菜大棚田间试验。其一,在番茄-菠菜轮作体系试验中,选取两种生态型的蚯蚓,分别为赤子爱胜蚓(Eisenia foetida)和威廉腔环毛蚯蚓(Metaphire guillemi);在有机物料表施或混施条件下,研究蚯蚓生态型和有机物料施用方式的交互作用对土壤肥力、作物生产、温室气体排放及硝酸盐淋溶的影响。其二,在黄瓜-菠菜轮作体系试验中,通过不同有机物料的搭配并接种赤子爱胜蚓,研究蚯蚓对土壤肥力及作物生产的影响,并从中选取最好的有机物料搭配方式,为农田生产应用及管理提供理论依据。研究结果如下:1、在番茄-菠菜轮作体系中,除了牛粪混施接种赤子爱胜蚓外,两种蚯蚓均显著地提高了土壤团聚体的平均重量直径(MWD)、硝态氮(NO3--N)、可溶性有机碳(DOC)、微生物生物量碳(MBC)、微生物生物量氮(MBN)和代谢熵(qCO2)。接种赤子爱胜蚓使土壤线虫总数降低30%～33%,接种威廉腔环蚓降低线虫总数31%～37%。在黄瓜-菠菜轮作体系中,在牛粪以及牛粪+食用菌渣的处理中接种赤子爱胜蚓,显著地提高土壤MWD、NO3--N、MBC、MBN和qCO2含量,而在施用商品有机肥的处理中,接种赤子爱胜蚓仅显著地提高了土壤NO3--N和qCO2含量。有机物料施用接种赤子爱胜蚯蚓均未显著影响土壤pH,但降低了土壤线虫总数及植食性线虫的数量。2、在番茄-菠菜轮作体系中,两种蚯蚓均显著地提高蔬菜产量18%～47%。接种赤子爱胜蚓显著地提高番茄果实和菠菜叶片中的可溶性糖和维生素C(Vc)含量,而对可溶性蛋白和硝酸盐含量未达到显著差异。接种威廉腔环毛蚓对蔬菜品质的影响均未达到显著水平。在黄瓜-菠菜轮作体系中,不同有机物料的施用下接种赤子爱胜蚓均显著地提高了黄瓜和菠菜的产量,其中最大的效果出现在牛粪+食用菌渣并接种蚯蚓的处理中。同时,在牛粪以及牛粪+食用菌渣的处理中接种赤子爱胜蚓均显著地提高黄瓜果实和菠菜叶片中可溶性糖和Vc含量,但对可溶性蛋白和硝酸盐含量无显著影响。3、在番茄-菠菜轮作体系中,接种蚯蚓显著地提高了累积的生态系统呼吸Recosyst(CO2)和N2O的排放量,分别为46%～87%和19%～25%。但对土壤累积CH4排放量及不同深度土壤渗漏水中NO3--N浓度未达到显著影响。其中,蚯蚓提高土壤N2O的原因主要是通过促进了土壤N的活性(NO3--N和MBN)和C的有效性(DOC)的增加,与蚯蚓生态型关系不大。4、在番茄-菠菜体系中,接种蚯蚓显著地提高了番茄根系(NPProot)和果实(NPPfruit)净初级生产力,提高了菠菜根系(NPProot)及地上部(NPPabove-ground)的净初级生产力。在作物生长季节尺度上,蚯蚓显著地提高了净综合净温室效应(net GWP)和碳排放当量(CEE),对净温室气体强度(netGHGI)和碳的效益比(CER)无显著影响。另外,蚯蚓显著地降低了土壤有机碳的变化量(ASOCD)和净生态系统碳收支(NECB)。在番茄季,接种赤子爱胜蚓和威廉腔环毛蚓分别降低NECB 14.4%～15.4%和15.8%～16.0%,在菠菜季,接种赤子爱胜蚓和威廉腔环毛蚓分别降低NECB 9.5%～13.0%和13.1%～14.1%。其中,土壤因子DOC、MWD和MBN与NECB呈现显著的负相关。蚯蚓对NECB的影响与蚯蚓生态型关系不明显。总之,在施用有机物料的菜地系统中,接种蚯蚓是一种有效的生物调控措施,显著地提高了土壤养分和微生物生物量及活性,改善了土壤结构,增加了作物产量,但也存在增加温室气体排放,净综合温室效应及生态系统碳支出的风险。本研究促进了全面理解蚯蚓在农田生态系统中的服务与功能,并为农业实际应用理论及经营管理提供了理论基础。更多还原

【Abstract】 Recently,high N inputs could result in a long list of problems such as soil acidification,soil structure degradation,microbial diversity loss,increased greenhouse gas emissions and NO3--N leaching into water systems.Reduction or replacement of chemical fertilizer by organic amendment has been considered as one of the most feasible ways to the development of sustainable agriculture.This dissertation aims to explore the feasibility and consequences of inoculating earthworms to field as a bio-manipulation approach following the organic amendment.As a soil ecosystem engineer,earthworm plays a critical role in in terrestrial ecosystem.Through burrowing,casting and mixing of litter and,soil,earthworm could influence soil physicochemical and biological properties.Numerous studies have reported that earthworms would benefit on soil ecosystem services,but their overall effects on environment have drawn little attention.On the basis of previous findings,two field experiments were set up to understand the earthworm ecological services in vegetable field under intensive managements such as extensive planting vegetables and organic amendements.First,in the.tomato-spinach rotation system,the field greenhouse experiment aims to explore the effects of two different earthworm species under the different ways of organic amendment including amendment at soil surface or incorporated into soil on earthworm-induced ecosystem servieces(crop yield and soil quality)and dis-services(N2O emissions and NO3--N leaching).Second,in the cucumber-spinach rotation system,the field experiment mainly aims to explore the effects of three different organic amendment in the presence of earthworm(Eisenia foetida)on ecosystem servieces(crop yield and soil quality)to provide the basis for appropriate organic amendment application and earthworm inoculation.The primary results as follows:1 In the tomato-spinach rotation agroecosystem,regardless of the vegetable season,the soil MWD,NO3--N,DOC,MBN and qCO2 significantly increased in the plots in which earthworms were introduced,except for those with E.foetida when manure was incorporated into the soil.In addition,E.foetida and M.guillemi significantly decreased the total nematode numbers by 30%to 33%and 31%to 37%,respectively.In the cucumber-spinach rotation agroecosystem,the soil MWD,NO3--N,MBN and qCO2significantly increased for the treatment,which the cattle manure and mushroom inoculated with E.foetida.No changes were found in the soil pH or NH4+-N contents due to earthworms were detected among the treatments.Meanwhile,E.foetida significantly decreased the total nematode numbers and herbivores nematode among all treatments.2 In the tomato-spinach rotation agroecosystem,earthworms additon significantly increased the crop yield by 18%to 47%.E.foetida increased significantly soluble sugar and Vitamin C of tomato and spinach,but no changes were found in the vegetable quality contents due to M.guillemi addition.In the cucumber-spinach rotation agroecosystem,the maximum crop yield within the treatment,which the cattle manure and mushroom inoculated E.foetida.Expect for the commercial organic fertilizer,other organic manure added E.foetida increased significantly soluble sugar and Vc of cucumber and spinach.No changes were found in the vegetable soluble protein or NO3--N contents due to earthworms were detected among the treatments3 In the tomato-spinach rotation agroecosystem,earthworms addition significantly increased the cumulative Recosyst(CO2)and N2O emission by 46%to 87%and 19%to 25%,respectively.However,it did not significantly increase the cumulative CH4 and leachate NO3--N concentration to a statistical level.Also,earthworm-induced N2O emissions were mainly attributed to the increase of soil N availability(NO3--N and microbial biomass N)and carbon(C)availability(dissolved organic C)regardless of earthworm ecological strategies.4 In the tomato-spinach rotation agroecosystem,earthworms addition significantly increased the total net primary productivity of tomato(NPProot and NPPfruit)and spinach(NPProot and NPPabove-ground)-Also,earthworm significantly increased the net global warming potential and carbon equivalent emissions at crop seasonal time scale regardless of earthworm ecological strategies.However,it did not significantly increased the net greenhouse gas intensity and carbon efficiency ratio.In addition,earthworm inoculated significantly decreased the net ecosystem carbon budget and soil organic carbon.In tomato season,the net ecosystem carbon budget was decreased by 14.4%to 15.4%and 15.8%to16.0%for the presence of E.foetida and M.guillemi,respectively.Similarly,in spinach season,the net ecosystem carbon budget was decreased by 9.5%to 13.0%and 13.1%to14.1%for the presence of E.foetida and M.guillemi,respectively.While the soil dissolved organic C,mean weight diameter and microbial biomass N by earthworms exerted negative effects on net ecosystem carbon budget.In conclusion,earthworm as a biological control technique significantly increased the crop yield,improved soil structure,enhanced soil nutrient and the microbial activity.However,earthworm significantly increased greenhous gas emissions,net global warming potential and the net ecosystem carbon budget in intensive agroecosystem.Therefore,this study not only promote the understanding of earthworm ecosystem service function,but also provided a practical theory and management for farmland.更多还原